Carbon Nanotubes Burst Out of the Lab
Fourteen years after the discovery of the pencil-shaped molecules called carbon nanotubes, scientists are finally learning to exploit their remarkable properties. Nanotubes are nine times as strong as steel and can transmit 1,000 times as much electrical current as copper, but they are difficult to manipulate because each tube is just 1/350,000 as wide as the period at the end of this sentence.
In August Ray Baughman at the University of Texas in Dallas and his colleagues reported a way to weave nanotubes into usefully large material. With the help of Australian wool spinners, researchers had already developed a method to twist the tubes into long fibers. Expanding on that work, the Texas group created sheets of nanotubes so thin that an acre of the material weighs just a quarter of a pound. The sheets are good electrical conductors; they can also withstand more than 34,000 pounds per square inch of force without tearing and can endure temperatures as high as 840 degrees Fahrenheit without losing strength or conductivity. The Department of Defense, along with manufacturers of helicopter blades, solar electric cells, and robotics, has expressed interest. Baughman has made a sheet 33 feet long, and he is hard at work expanding his process.
Meanwhile, two teams are developing medical applications of nanotubes, taking advantage of the human body's ability to absorb carbon. Stanford University chemists have fabricated cancer-killing nanotubes that sneak inside tumor cells, and researchers at the University of California at Riverside are using nanotubes to speed the healing of broken bones. Materials scientist Robert Haddon has demonstrated that the bone-forming mineral hydroxyapatite will grow around a nanotube scaffold, replacing the collagen fibrils that grow naturally. "Bone needs to be strong but a little bit flexible," he says. "It's hard to imagine a better material than a carbon nanotube." —Zach Zorich
Tissue Engineers Cook Up Plan for Lab-Grown Meat
Most of us avoid thinking too hard about the origins of our dinners. We happily eat chicken nuggets, willfully forgetting that they are a meat product derived from formerly living birds. Now science is prepared to make our cognitive dissonance complete. Last June, in a paper published in the journal Tissue Engineering, an international team of researchers proposed a new kind of food handmade for sensitive carnivores (and maybe even vegetarians): meat that comes from a laboratory instead of a farm.
Clinical research scientists routinely grow muscle cells in the lab. And NASA-funded experiments have succeeded in culturing turkey muscle cells and goldfish cells as a potential way to feed astronauts on long space missions. Jason Matheny, a graduate student in agricultural economics and public health at the University of Maryland, and his colleagues turned this scheme earthward, proposing two methods for growing meat in bulk. One would culture thin sheets of meat, seeded by cells from a living animal, on a reusable polymer scaffold; the other would grow meat on small edible beads that stretch with changes in temperature.
Currently the process is far too expensive to bring lab-grown meat to the supermarket. A tasty fake steak is an even more distant dream: To have the structure of filet mignon, muscle tissue needs blood vessels, a major challenge to tissue engineers. Still, Matheny says that within several years, lab meat could be used in Spam, sausage, and even chicken nuggets. Europe has taken an interest. The Dutch government has invested $2.4 million in a project that would cultivate pork from stem cells.
But will people eat it? Matheny thinks so. "There's nothing natural about a chicken that's given growth promoters and raised in a shed with 10,000 others," he says. "As consumers become educated, a product like this would gain appeal." —Sarah Webb